Multiple pushbutton switch with selective latching mechanism



Oct. 12, 1965 P. HUTT ETAL MULTIPLE PUSHBUTTON SWITCH WITH SELECTIVE LATCHING MECHANISM Filed Jan. 2, 1962 Inventors Philip Hutt George C. Mapelsden QM Thelr Attorney United States Patent 3,211,846 MULTIPLE PUSHBUTTON SWITCH WITH SELECTIVE LATCG MECHANISM Philip Hutt, Milford, and George C. Mapelsden, Easton,

Conn, assignors to General Electric Company, a corporation of New York Filed Jan. 2, 1962, Ser. No. 163,648 8 Claims. (Q1. 200-) This invention relates to a pushbutton switch and particularly a multiple pushbutton switch with a series of manually controlled reciprocating sliders for controlling the operation of several circuits connected through the switch.

Mutiple pushbutton switches have been used in great numbers as appliance switches for electric ranges, washing machines, and room air conditioners, etc., to control the circuitry thereof. In many of these applications, it has been found desirable to provide a simplified and efficient means to achieve selective control of one or more switches by successive depressions of a single pushbutton. Such a control arrangement is often referred to by those skilled in the art as push-push action.

The principal object of the present invention is to provide a multiple pushbutton switch with a novel low cost means for obtaining push-push action.

A further object of this invention is to provide an improved slider operated multiple pushbutton switch wherein a selective latching mechanism is utilized in conjunction with a slider to obtain push-push action for an associated pushrod.

In carrying out the present invention, in one form thereof, it is applied to a multiple pushbutton switch with elongated movable sliders arranged in a switch housing. These sliders have a series of inclined working surfaces that are acted upon by pushrods, and cam surfaces for engaging movable contact supporting arms of the switch. Depression of certain of the pushrods causes coaction thereof with certain inclined surfaces of one or more of the sliders to thus move certain sliders longitudinally and return a previously depressed pushrod back to its outermost position. At the same time, the cam surfaces of the sliders act upon certain predetermined movable contacts of the switch within the switch housing to move them toward or away from their associated fixed contacts and thus either open or close circuits to the switch.

By the present invention and in one form thereof, a slider is constructed so that it has a projection formed thereon which extends outwardly from an aperture in the switch housing. This particular slider also includes a working surface having an inclined edge for coacting with an associated pushrod to move the slider projection in a particular direction in response to depression of the pushrod. The slider also includes one or more cam surfaces for controlling an associated contact carrying switch arm. A selective latching mechanism is positioned upon the outside of the switch housing. This mechanism includes a spring biased plunger which engages the slider projection to bias the one slider to a normal position. The biasing force exerted by the plunger upon the slider projection is in opposition to the direction of movement of the slider when the pushrod is depressed. The plunger of the latching mechanism is retracted to a latched posi tion every other time the pushrod is depressed and coacts with the slider projection to selectively control the longitudinal movement of the slider in response to successive reciprocations of the pushrod. Thus, the switch arm controlled by the slider with the projection is operated first to one position when the pushrod is depressed and released, and then to another position when the pushrod is subsequently depressed and released. Such an arrangement provides a low cost and efficient means for operating one or more switches in response to successive de pressions of a single pushrod.

Further aspects of this invention will become apparent hereinafter, and the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which we regard as our invention. The invention, as to organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description when taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a front elevational view of a multiple pushbutton switch embodying the present invention in one form thereof;

FIG. 2 is a bottom plan View of the switch;

FIG. 3 is a cross-sectional view taken generally on the line 33 of FIG. 1;

FIG. 4 is a front elevational view of the switch partially broken away and partially in section;

FIG. 5 is a fragmentary elevation view of the selective latching device, partially in section to show the interior thereof;

FIG. 6 is a cross-sectional view taken along the line 6-6 of FIG. 5;

FIG. 7 is a fragmentary front elevation view of part of the slider which coacts with the selective latching device, the view showing the positioning of two switch arms when the push-push pushrod is fully depressed from its position shown in FIG. 4; and

FIG. 8 is a view similar to FIG. 7 showing the positioning of the switch arms when the push-push pushrod is released after depression from its position shown in FIG. 4.

Referring in detail to the drawing and in particular to FIGS. 1 and 2, there is shown a multiple push-button switch 1 wherein the present invention has been advantageously employed. The switch housing 3 comprises hollow base 5 and relatively thin cover plate 7, both of which are formed of suitable insulating material and cooperate to provide a compact supporting structure for the operating mechanism of the switch. Cover plate 7 has two oppositely disposed rows of narrow slots 9 through which terminals 11 and 13 extend. Terminals 11 are connected to and support fixed contacts 15, and terminals 13 are connected to and support movable contacts 17. (See FIGS. 3 and 4.) Cover plate 7 is securely attached to base 5 by the terminals 11 and 13 of the fixed and movable contacts. These terminals each extend through cover plate slots 9 and the aligned or overlying slots 23 in the base 5 (FIG. 3), with appropriate projecting fingers 25 adjacent the outer surfaces of the base and plate being lapped over in the well-known manner to hold the terminals in place and secure together the cover and base.

To actuate multiple switch 1, pushrods 27 extend downwardly through top wall 219 of base 5 into the hollow portion thereof (FIGS. 1 and 3). The pushrods .27 have bifurcated outer ends (not shown) for engaging pushbuttons 35a-35e. Each of the pushbuttons 35a, 3 50, and 35e are attached to the outer end of a single pushrod 27. However, the pushbuttons 35b and 35d are each attached to the outer ends of an adjacent pair of pushrods 27. By arranging the pushnods 27 in pairs for control by the pushbuttons 35b and 35d, a means is obtained for operating these pairs in unison and effectively controlling and balancing these push'buttons during the reciprocation thereof.

The pushrods 27 have cylindrically configured actuating portions 30 (FIG 3) formed on their inner ends which cooperate with various inclined upper working edges 32 of sliders 31 and 31a. (See FIG. 3.) Sliders 31 are disposed in parallel relationship in the well-known manner, and reciprocate longitudinally to actuate movable contact supporting arms 33. The structure and operation of slider 3 1:! shall be described hereinafter.

clined working surfaces 32 of the upper edges of the sliders 31 are so arranged on the different sliders that only one of the pushbuttons a-35d may be fully depressed at any one time. As is thus Well known in the art, the depression of one of the pushbuttons 35a-35d causes the longitudinal movement of one or more of the sliders 3 1, and this movement actuates one or more pairs of contacts of the switch by engagement of cam surfaces 64 of the sliders with movable contact supporting arms 33.

When any particular one of the pushbuttons 3'5a-35d of the improved switch 1 is depressed from its outermost position, the pushrod 27 or the pair of pushrods '27 controlled thereby operate the sliders 3 1 to open or close certain switches. when any one of the pushbuttons 35a- 35d is depressed, it is then thereafter necessary to depress another one of these pushbuttons in order to operate the switches controlled by the initially depressed pushbutt-on hack to their original position. The present invention concerns itself with an improved means for obtaining twoposition control, or on-ofi action of one or more pairs of contacts by successive depressions of the single pushbutton 35s. The structural arrangement for achieving this function in an expeditious manner shall now be described.

In the illustrated switch, slider 31a is somewhat similar in construction to the sliders 3 1 and is also disposed in parallel side-by-side relationship to sliders 31 (FIG. 3). But slider 31a operates independently of the three sliders 31 to control movable supporting arms 33a and 33b (FIG. 4). More particularly, slider 31a is of elongated relatively flat construction (FIG. 3 and FIG. 4) and includes an inclined working surface 32 which underlies the pushrod '27 controlled by pushbutton 35e. On the edge of slider 31a opposite the edge wherein working surface 32 is formed, spaced apart cam ming surfaces 34a and 341) are located. The carnming surfaces 34a and 34b engage movable contact carrying :arms 3 3a and 3312 respectively when slider 31a is in the position shown in FIG. 4, and the surfaces 34a and 34b then hold the movable contacts 17 carried thereby in the open position.

To effectively enable pushbutton 35a to alternately operate the switch including arm 34a to its open or closed position in response to successive cycles of reciprocation of pushbutton 35s, the present invention provides the selective latching device 37 for controlling the reciprocating movement of slider 31a. (See FIG. 4.) Device 37 generally comprises an elongated supporting bracket 39, a driving plunger 41 extending into a partially enclosed framework described by the bracket 39, and a spring biased ratchet mechanism 43 disposed within the framework for coaction with the driving plunger 41. Bracket 39 includes two pairs of opposed side walls 47 (FIGS. 1 and 3) which are turned over perpendicularly from bottom section 49, and opposed end walls :51 which are turned over in like manner at the ends of bottom section 49 (FIGS. 1, 3, and 4). The end walls 51 have apertures 53 formed therein. For attaching bracket 39 to the housing of the switch, tabs 55 are formed on each one of an oppositely disposed pair of side walls '47 (as shown in FIG. 4). The opposed tabs 55 are thus extended through appropriate apertures formed in cover plate 7 and staked over on the inside of the switch for rigid attachment of the bracket to the underside of the cover plate in the manner illustrated in FIG. 4.

The driving plunger 41 is extended through the aperture 53 (FIG. 3) of the end wall 51 on the right side of the latching device (viewing FIG. 4). As shown in FIG. 5, plunger 41 has a series of teeth 57 arranged in annular fashion on its inner end. The teeth 57 are disposed Within a hollow shouldered sleeve 59 which rests upon and is rigidly attached to the inner surface of bottom section 49 of the bracket. Sleeve 59 has a series of peripheral ratchet teeth '61 formed on its left side, viewing FIG. 5, and a series of angularly spaced grooves 62a and 6% extending axially along its inner cylindrical wall. The teeth 61 of sleeve 59 cooperate with a series of ratchet teeth 63 formed on ratchet member 65. More particularly, ratchet member 65 includes an elongated sleeve section 67 which extends into a blind bore of driving plunger 41. Teeth 63 of ratchet member 6 5 are engaged and driven by teeth 57 of the driving plunger and coact with teeth 57 of the plunger and teeth 61 of the sleeve to rotate the ratchet member from one angular position to another angular position upon each reciprocation of the plunger 41. Each time plunger 41 reciprocates, radial wings or ribs 66 of ratchet member 65 rot-ate irom one set of grooves 621; in sleeve 59 to the other set of grooves 62b. One set of the grooves 6% has steps 64 (FIG. 6) formed thereon to limit return movement of the plunger 41 to an intermediate position after it has been depressed, The other set of grooves 62a allows plunger 41 to return to its normal outermost position, where it is shown in FIG. 4 after it has been depressed. It will thus be understood that the device 37 serves to alternately latch and unlatch the plunger '41 with its outer end 69 thereby returning to intermediate and outermost axial positions, respectively.

For operating plunger 41 of device 37 to its outermost or intermediate position after each depression thereof, a driven plunger 45 (FIG. 4) is located on the left side of sleeve 59. The inner end of plunger 45 (not shown) enters sleeve 59 where it engages ratchet member 65, and its outer end extends outwardly to the left, as shown in FIG. 4, through the aperture 53 formed on the left end wall 51. An annular shoulder 68 is formed on plunger 45 near its inner end. A coiled compression spring 71 is positioned around driven plunger 45. Spring 71 runs in compression between the inner surface of the left end wall 51 and the annular shoulder 68 of the plunger 45 to continuously bias the inner end of plunger 45 to the right (viewing FIG. 4). The inner end of the driven plunger 45 thus engages the inner face of the ratchet member 65 (FIG. 6) and biases the teeth 63 of member 65 into engagement with teeth 61 of the shouldered sleeve and teeth 57 of the driving plunger 41.

For a detailed description of the operation of selective latching mechanism 37, attention is now directed to FIGS. 4-6. When the outer end 69 of driving plunger 41 is depressed to the left from the outermost position, where it is shown in FIG. 4, the teeth 57 on the inner end of the plunger 41 are in misaligned engagement with the ratchet teeth 63 of member 65 and member 65 is moved axially with plunger 41 to the general position shown by dotted lines in FIG. 5. Just before the member 65 has reached its inner most depressed position, teeth 63 thereof lowed to close, since these switches are coact with teeth 57 of the plunger to rotate the member 65 through a small angle. The coaction of the teeth 57 of the plunger 41 with teeth 63 of member 65 thus causes rotation of member 65 in the same direction each time plunger 41 is depressed. As the driving plunger 41 moves to its depressed position, it acts against the compressive force of spring 71. When the outer end of the driving plunger 41 is then released, the inner end of driven plunger 45 acts upon the adjacent end of ratchet member 65 and moves it back to the right from its depressed position. The ratchet teeth 63 of member 65 thereupon engage the teeth 61 of sleeve 59 and rotate the ratchet member 65 still further in the same direction of rotation to their latched position (i.e., with wings 66 of member 65 latched at steps 64 of grooves 62b). The outer end 69 of plunger 41 is then in its dotted intermediate position (FIG. 5). When driving plunger 41 is subsequently again depressed, the teeth 57 of the driving plunger again act upon the ratchet teeth 63 of member 65 in the same manner as already described and the spring 71 again acts upon the ratchet member 65, with the ratchet teeth 63 of member 65 being rotated angularly into unlatching engagement with the teeth 61 of the sleeve (i.e., with wings 66 of member 65 located in elongated grooves 62a). Driving plunger 41 is thereupon returned by spring 71 to its original or undepressed position, as shown in full in FIGS. 4 and 5.

Having now described the operation of the selective latching device 37, attention is directed to FIGS. 3 and 4 for a detailed description of the manner in which the selective latching device 37 is utilized to provide push-push action for pushbutton 35e in the switch 1. The slider 31a, which is shown in the foreground of FIG. 4, includes near its right end a single inclined upper working edge 32 which generally underlies the pushrod 27 controlled by pushbutton 35c. The upper edge of slider 31a also includes a series of spaced apart rectangularly configured recesses 75 which provide clearance for but do not have any particular effect upon the cylindrical portions 30 of the other pushrods. The bottom edge of slider 31 has cam surfaces 34a and 34b formed thereon. The cam surfaces 34a and 34b are disposed near movable contact arms 33a and 3312 respectively for the operation thereof.

Between the camming surfaces 34a and 3412, a projection 77 is formed in the bottom edge of slider 31a. Projection 77 extends outwardly in perpendicular fashion from the longitudinal axis of the slider 31a and also extends outwardly from the switch housing through an elongated slot 79 (FIG. 4) formed in cover plate 7. The

projection 77 coacts with the outer end 69 of the driving plunger 41 of the selective latching mechanism 37 to control the positioning of slider 31a in response to successive reciprocations of pushbutton 35c.

For a description of the operation of slider 31a and the switches controlled thereby, attention is directed to FIGS. 4, 7, and 8. When pushbutton 35a is in its outermost position, as shown in FIG. 4, the outer end 69 of driving plunger 41 of the selective latching mechanism 37 is in its extreme right position where it engages projection 77. The slider 31a is thus urged by spring 71 into the position where it is shown in FIG. 4. When pushbutton 35c is then depressed, the actuating portion 30 of the pushrod attached to pushbutton 35e engages working surface 32 of the slider 3 1a and cams slider 31a to the left. Projection 77 of slider 31a thus moves to the left, viewing FIG. 4, and thereby forces plunger 41 to move against biasing spring 71 to its innermost depressed position (FIG. 7). When plunger 41 is in its innermost depressed position, as shown in FIG. 7, the cam surfaces 340! and 34b disengage the movable contact supporting arms 33a and 33b which they control. The contacts 15 and 17 which are controlled by the movable arms 33a and 33 b are then alnormally spring biased to a closed position.

When pushbutton 3512 is released from its innermost depressed position (FIG. 7), spring 71 returns the outer end 69 of plunger 41 to an intermediate position (shown by a dotted line in FIG. 4, and also shown in FIG. 8). The return movement of plunger 41 to the right after its depression is limited or stopped by the selective latching device 37. With plunger 41 in this position, the slider 31a is also returned to an intermediate position. The slider 31a is held in its intermediate position with projection 77 in contiguity to end 69 of the plunger, as shown in FIG. 8, by means of the engagement of movable contact arm 33a with shoulder 81 of cam surface 34a. With the slider 31a in its intermediate position, the switch arm 33a remains closed and the switch arm 33b is open.

When the pushbutton 35s is then subsequently depressed, after it first completes a reciprocation from its position shown in FIG. 4, the pushrod 27 controlled thereby again acts upon working surface 32 of the slider 31a to move slider 31a to the left (i.e., from the position of FIG. 8 to the position of FIG. 7). Projection 77 of the slider 31a then again acts upon the outer end 69 of plunger 41 and moves the plunger 41 to its extreme depressed position (FIG. 7). Switch arm 33b is then again allowed to close, as previously described. Upon release of the subsequently depressed plunger 41, spring 71 thereupon returns the outer end of the plunger 41 to its original position and slider 31a returns to its original position (both of these positions being shown in full in FIG. 4). The switch arms 33a and 3312 which are controlled by cam surfaces 34a and 34b are both then cammed into their open positions against the biasing forces of the arms. It will now therefore be understood that the switch arm 33a which is controlled by cam surface 34a is operated first to a closed position upon a first depression and release of pushbutton 35c and then is returned to an open position upon a second or successive depression and release of pushbutton 356. The switch including arm 33a may be effectively utilized in a circuit to provide on-otf action by successive pushes and releases of a single pushbutton. It will further be understood that the switch arm 3311 which is controlled by cam surface 34b is part of the type of switch often referred to .as a momentary switch, since its contacts are closed momentarily upon each depression of pushbutton 352 .and then immediately restored to an open condition upon release of the pushbutton 356.

It will be understood from the foregoing that the new and improved pushbutton switch of the present invention such as is herein illustrated provides a simple and efficient means for alternately operating one or more switches between its positions by means of successive reciprocations of a single pushbutton. It should be realized that certain aspects of the present invention may be incorporated efficiently and beneficially in other various types of pushbutton switches.

While in accordance with the Patent Statutes, we have described what at present is considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from this invention, and we, therefore, aim in the following claims to cover all such equivalent variations as fall within the true spirit and scope of this invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A multiple pushbutton switch comprising a housing including a base, a plurality of pushrods mounted on said housing for respective movement between outer and depressed positions in relation to said housing a plurality of reciprocating sliders carried by said housing and extending transversely of said pushrods, said pushrods engaging said sliders to effect an axial movement thereof, switch means supported by said housing and including at least one switch element actuated by said sliders,

one of said sliders having an inclined edge engaging one of 7 said pushrods to cause said slider to move in response to depression of said one pushrod, slider control means including a driving plunger movable between an inner position, a latched intermediate position, and an extended position, means biasing said plunger toward said extended position, means on said slider engaging said plunger so that said slider moves said plunger to its inner position when said slider is shifted by the depression of said pushrod and said plunger returns said slider toward 'its initial position when said pushrod is released, and a ratchet mechanism engaging said plunger and latching said plunger in its intermediate position following every second actuation of said slider by said pushrod, whereby said slider is also returned only to an intermediate position following every second depression of said pushrod, and a surface on said slider engaging said switching means for actuating said switching element to a predetermined position depending upon the position of said slider.

2. A multiple pushbutton switch comprising a housing including a base, a plurality of pushrods mounted on said housing, a plurality of reciprocating sliders carried by said housing and engageable with said pushrods, said sliders being moved in response to movement of said pushrods, contact means including a plurality of movable contacts supported by said housing and operated by said sliders, one of said sliders having a projection extending outwardly from said housing and being movable between first and second positions, an actuating recess formed on said one slider, said actuating recess including an inclined edge for engagement with one associated pushrod to move said slider from said first to said second position in response to depression of said one pushrod, first and second of said movable contacts arranged for actuation to respective closed positions by movement of said one slider from said first to said second position, said first movable contact being actuated to the open position upon movement of said slider from the second toward the first position, and slider control means mounted on the exterior of said housing, said control means engaging the projection of said one slider and biasing said one slider to return said slider toward said first position, said control means including latching means for limiting the return movement of said one slider to an intermediate position between said first and second positions every other time said one slider is moved to said second position and released.

3. A pushbutton switch comprising an insulating support, a pushrod mounted on said support, contact means including at least one movable contact mounted on said support, a slider mounted on said support for movement between at least first and second positions to actuate said movable contact, means on said slider engaging said pushrod for moving said slider from one of said positions to the other in response to depression of said pushrod, and slider control means engaging said slider for effecting a return movement of said slider following a depression of said pushrod, said control means including a latching means for limiting the return movement of said slider to an intermediate position between said first and second positions following every alternate depression of said pushrod, and a cam surface formed on said slider and engaging said contact means for actuating said contact means to a predetermined position depending upon the position of said slider.

4. A pushbutton switch comprising an insulating support, a manually operable pushrod mounted on said support, contact means including first and second movable contacts mounted on said support, a slider mounted on said support and movable between at least first and second positions, said slider being movable transversely of the pushrod, an inclined surface formed on said slider and engageable with said pushrod for moving said slider to said second position from said first position in response to a depression of said pushrod, cam means on said slider engaging said contact means for actuating said first and second movable contact to predetermined positions depending on the position of said slider, a slider control means biasing said slider to return said slider toward said first position, said slider control means including a latching means for limiting the return movement of said slider to an intermediate position between said first and second positions every alternate time said slider is moved to said second position and released.

5. A multiple pushbutton switch comprising a recessed base, a cover member fastened to said base to provide a switch housing, a slot formed in said cover member, a plurality of pushrods mounted on said base, a plurality of reciprocating sliders disposed within said base, engageable with said pushrods and responsive to movement of said pushrods, said sliders extending and moving transversely of said pushrods, contact means including a plurality of movable contacts supported by said base for operation by said sliders, one of said sliders having a projection formed thereon, said projection extending outwardly from said base through the slot formed in said cover member, said one slider also having an inclined edge for engagement with one associated pushrod thereby to move said slider projection in response to depression of said one pushrod, said slider being operable between at least first and second positions, and a slider control means mounted on the exterior of said housing and engaging said projection for driving said slider towards said first position following a depression of said pushrod, said control means including a latching means for limiting the return movement of the slider to an intermediate position between said first and second positions every alternate time said one slider is actuated by said pushrod to said second position and released.

6. The switch of claim 5 wherein the slider control means includes a driving plunger spring biased into engagement with said projection of the one slider, and said latching means engages said plunger for selectively latching the plunger to limit said return movement of the slider to said intermediate position.

7. A multiple pushbutton switch comprising a base, a plurality of pushrods mounted on said base, a plurality of reciprocating sliders carried by said base and engageable with said pushrods and responsive to movement of said pushrods, said slider moving transversely of said pushrods, contact means including a plurality of movable contacts supported by said base for operation by said sliders, one of said sliders having an inclined edge engageable with one associated pushrod to move said slider in response to depression of said one pushrod, said one slider being movable between at least first and second positions, and slider control means engaging said one slider for biasing said one slider to return said slider toward said first position, said control means including latching means for limiting the return movement of said one slider to an intermediate position between said first and second positions every other time said one slider is moved to said second position and released, and a means formed on said slider and engaging said contact means for actuating said contact means to a predetermined position depending upon the position of said slider.

8. A pushbutton switch comprising an insulating support, a pushrod mounted for reciprocation on said support, contact means including at least one movable contact disposed on said support, a slider mounted on said housing and movable between first and second positions toractuate said movable contact, means on said slider engageable with said pushrod for causing said slider to be moved from said first position to said second position in response to depression of said pushrod, and a slider control means including a driving plunger, a latching mechanism for said plunger, spring means biasing said plunger 10 to return said slider from said second position towards References Cited by the Examiner said first position, and said latching mechanism engaging UNITED STATES PATENTS said plunger to limit the movement of said plunger and thereby limit the return movement of said slider to an in- 2,431,904 12/47 Andrewstermediate position between said first and second positions 5 19 316 8/50 Armstrong 200 5 on every other depression of said pushrod, said slider ac- 2691702 10/54 Alhson 20O 5 X tuating said movable contact alternately to open and closed positions upon said successive depressions of said KATHLEEN CLAFFY Prlmary Exammer pushrod. BERNARD A. GILHEANY, Examiner. 

1. A MULTIPLE PUSHBUTTON SWITCH COMPRISING A HOUSING INCLUDING A BASE, A PLURALITY OF PUSHRODS MOUNTED ON SAID HOUSING FOR RESPECTIVE MOVEMENT BETWEEN OUTER AND DEPRESSED POSITIONS IN RELATION TO SAID HOUSING A PLURALITY OF RECIPROCATING SLIDERS CARRIED BY SAID HOUSING AND EXTENDING TRANSVERSELY OF SAID PUSHRODS, SAID PUSHRODS ENGAGING SAID SLIDERS TO EFFECT AN AXIAL MOVEMENT THEREOF, SWITCH MEANS SUPPORTED BY SAID HOUSING AND INCLUDING AT LEAST SWITCH ELEMENT ACTUATED BY SAID SLIDERS, ONE OF SAID SLIDERS HAVING AN INCLINED EDGE ENGAGING ONE OF SAID PUSHRODS TO CAUSE SAID SLIDER T MOVE IN RESPONSE TO DEPRESSION OF SAID ONE PUSHROD, SLIDER CONTROL MEANS INCLUDING A DRIVING LUNGER MOVABLE BETWEEN AN INNER POSITION A LATCHED INTERMEDIATE POSITION, AND AN EXTENDED POSITION, MEANS BIASING SAID PLUNGER TOWARD SAID EXTENDED POSITION, MEANS ON SAID SLIDER ENGAGING SAID PLUNGER SO THAT SAID SLIDER MOVES SAID PLUNGER TO ITS INNER POSITION WHEN SAID SLIDER IS SHIFTED BY THE DEPRESSION OF SAID PUSHROD AND SAID PLUNGER RETURNS SAID SLIDER TOWARD ITS INTITIAL POSITION WHEN SAID PUSHROD IS RELEASED, AND A RATCHET MECHANISM ENGAGING SAID PLUNGER AND LATCHING SAID PLUNGER IN ITS INTERMEDIATE POSITION FOLLOWING EVERY SECOND ACTUATION OF SAID SLIDER BY SAID PUSHROD, WHEREBY SAID SLIDER IS ALSO RETURNED ONLY TO AN INTERMEDIATE POSITION FOLLOWING EVERY SECOND DEPRESSION OF SAID PUSHROD, AND A SURFACE ON SAID SLIDER ENGAGING SAID SWITCHING MEANS FOR ACTUATING SAID SWITCHING ELEMENT TO A PREDETERMINED POSITION DEPENDING UPON THE POSITION OF SAID SLIDER. 